Acta Crystallographica Section D

Biological Crystallography

Volume 59, Part 3 (March 2003)

crystallization papers

Acta Cryst. (2003). D59, 597-599 [ doi:10.1107/S0907444902023466 ]

The production, purification and crystallization of a pocilloporin pigment from a reef-forming coral

T. Beddoe, M. Ling, S. Dove, O. Hoegh-Guldberg, R. J. Devenish, M. Prescott and J. Rossjohn

Abstract: Reef-building corals contain fluorescent pigments termed pocilloporins that function by regulating the light environment of coral and acting as a photoprotectant in excessive sunlight. These pocilloporins are related to the monomeric green fluorescent protein and the tetrameric DsRed fluorescent proteins, which have widespread use as biotechnological tools. An intensely blue-coloured pocilloporin, termed Rtms5, was expressed in Escherichia coli, purified and crystallized. Rtms5 was shown to be tetrameric, with deep blue crystals that diffract to 2.2 Å resolution and belong to space group I4₁22. The colour of this pocilloporin was observed to be sensitive to pH and a yellow (pH 3.5) and a red form (pH 4.5) of Rtms5 were also crystallized. These crystals belong to space group P4₂22 and diffract to 2.4 Å resolution or better.

Keywords: pocilloporins; pigments.